S000001599 [Member] Annual Total Returns |
12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Tax-Exempt Bond Fund | Class S | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 4.26% | 1.76% | 6.11% | (7.58%) | 2.19% | 4.05% | 7.10% | 1.45% | 4.69% | 0.15% |